and \(\underline{\Xi }_{Q_0}\)  is
the vector of Riemann constants (cf.(A.45) [1]}). Moreover,
The Abel map linearizes the auxiliary divisors
\(\mathcal {D}_{\hat{\underline{\mu }}(x,t_{\underline{r}})},\mathcal {D}_{\hat{\underline{\nu }}(x,t_{\underline{r}})}\) 
in the sense that
\(\underline{\alpha }_{Q_0}(\mathcal {D}_{\underline{\hat{\mu }}(x,t_{\underline{r}})})=&\underline{\alpha }_{Q_0}(\mathcal {D}_{\underline{\hat{\mu }}(x_0,t_{0,\underline{r}})})-i\underline{U}_0^{(2)}(x-x_0)-i\widetilde{\underline{U}}_{\underline{r}}^{(2)}(t-t_{0,\underline{r}}),\\\underline{\alpha }_{Q_0}(\mathcal {D}_{\underline{\hat{\nu }}(x,t_{\underline{r}})})=&\underline{\alpha }_{Q_0}(\mathcal {D}_{\underline{\hat{\nu }}(x_0,t_{0,\underline{r}})})-i\underline{U}_0^{(2)}(x-x_0)-i\widetilde{\underline{U}}_{\underline{r}}^{(2)}(t-t_{0,\underline{r}}).\) 
